地面和地下物流系统运输竞争分配问题

On the Competitive Transportation Distribution Problem Between the Ground and Underground Logistics System

地下物流系统是一类正在兴起的物流系统,是传统地面物流系统的有益补充.因其在缓解城市交通拥堵、运输效率低下、环境污染高等问题的潜在优势,地下物流系统正逐渐引起研究人员的广泛关注.文章研究了地面和地下物流系统共存时,物流运输在二者之间的竞争分配问题.首先,将地下物流系统抽象为三层物流网络,结合地下物流管道容量、地下物流节点服务能力等约束,构建了以总成本最小为目标的约束非线性规划模型.该模型综合考虑了地面和地下物流系统的运输成本、损耗成本;其次,结合B aumol-Wolfe模型的线性近似思想,通过逐次计算边际损耗成本,设计了求解该约束非线性规划模型的线性近似迭代算法;再次,通过对比存在竞争和无竞争时的仿真结果,验证了模型的可行性和有效性.最后,通过对管道容量、节点服务能力和单位损耗成本、成本比例等进行参数分析,探讨了参数变化对地面和地下物流系统运输竞争分配的影响,对比了所提的算法与全局优化算法、遗传算法的求解效果.结果表明:地下物流系统应充分平衡需求量与供应量之间的关系,并合理设置管道容量、节点服务能力和成本比例等;所设计的算法能在合理的计算时间内较好地求解该问题.

The underground logistics system is a kind of emerging logistics system,which is a useful alternative to the traditional ground logistics system.Due to its potential advantages in alleviating traffic congestion,low transportation efficiency and high environmental pollution in large cities,the underground logistics system is gradually attracting increasing attention of the researchers.This paper studies the competitive distribution of logistics transportation between the ground and underground logistics system.Firstly,the underground logistics system is characterized by a three-tier logistics network;and then,by taking both the capacity of the underground logistics pipelines and the service ability of the underground logistics nodes into considerations,a constrained nonlinear programming model is proposed with the objective of minimizing the total cost,which includes the transportation cost and the loss cost of both the ground and underground logistics system;secondly,inspired by the linear approximation of Baumol-Wolfe model,a linear approximation iterative algorithm is employed to solve the constrained nonlinear programming model by calculating the marginal loss cost;finally,the feasibility and effectiveness of the proposed model are verified by comparing the simulation results of both the competition and non-competition distribution of logistics transportation.Furthermore,the effect of the transportation distribution on the ground and underground logistics system is demonstrated by the parameter analysis of the pipelines’capacity,the nodes’service capability,the pipelines’unit loss cost,and the cost ratio.The comparisons again the proposed algorithm,global optimization algorithm,and genetic algorithm are also presented in terms of solution quality.The results have shown that the underground logistics system should sufficiently balance the relationship between demand and supply,and properly design the pipelines’capacity,the nodes’service capabilities,and the unit cost ratio,and the proposed algorithm can solve our problem effectively in the reasonable computational time.